Novel HSP90 inhibitor NVP-AUY922 enhances the anti-tumor effect of temsirolimus against oral squamous cell carcinoma

AUY922 induces retinal toxicity through attenuating TRPM1

Background

Ocular adverse events are common dose-limiting toxicities in cancer patients treated with HSP90 inhibitors, such as AUY922; however, the pathology and molecular mechanisms that mediate AUY922-induced retinal toxicity remain undescribed.

Methods

The impact of AUY922 on mouse retinas and cell lines was comprehensively investigated using isobaric tags for relative and absolute quantitation (iTRAQ)‑based proteomic profiling and pathway enrichment analysis, immunohistochemistry and immunofluorescence staining, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, MTT assay, colony formation assay, and western blot analysis. The effect of AUY922 on the Transient Receptor Potential cation channel subfamily M member 1 (TRPM1)-HSP90 chaperone complex was characterized by coimmunoprecipitation. TRPM1-regulated gene expression was analyzed by RNAseq analysis and gene set enrichment analysis (GSEA). The role of TRPM1 was assessed using both loss-of-function and gain-of-function approaches.

Results

Here, we show that the treatment with AUY922 induced retinal damage and cell apoptosis, dysregulated the photoreceptor and retinal pigment epithelium (RPE) layers, and reduced TRPM1 expression. Proteomic profiling and functional annotation of differentially expressed proteins reveals that those related to stress responses, protein folding processes, regulation of apoptosis, cell cycle and growth, reactive oxygen species (ROS) response, cell junction assembly and adhesion regulation, and proton transmembrane transport were significantly enriched in AUY922-treated cells. We found that AUY922 triggered caspase-3-dependent cell apoptosis, increased ROS production and inhibited cell growth. We determined that TRPM1 is a bona fide HSP90 client and characterized that AUY922 may reduce TRPM1 expression by disrupting the CDC37-HSP90 chaperone complex. Additionally, GSEA revealed that TRPM1-regulated genes were associated with retinal morphogenesis in camera-type eyes and the JAK-STAT cascade. Finally, gain-of-function and loss-of-function analyses validated the finding that TRPM1 mediated the cell apoptosis, ROS production and growth inhibition induced by AUY922.

Conclusions

Our study demonstrates the pathology of AUY922-induced retinal toxicity in vivo. TRPM1 is an HSP90 client, regulates photoreceptor morphology and function, and mediates AUY922-induced cytotoxicity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12929-021-00751-5.

Identification of four key prognostic genes and three potential drugs in human papillomavirus negative head and neck squamous cell carcinoma

BACKGROUND

Head and neck squamous cell carcinoma (HNSCC) is a common tumor worldwide with poor prognosis. The pathogenesis of human papillomavirus (HPV)-positive and HPV-negative HNSCCs differs. However, few studies have considered the HPV status when identifying biomarkers for HNSCC. Thus, the identification of biomarkers for HPV-positive and HPV-negative HNSCCs is urgently needed.

METHODS

Three microarray datasets from Gene Expression Omnibus (GEO) were analyzed, and the differentially expressed genes (DEGs) were obtained. Then, functional enrichment pathway analysis was performed and protein-protein interaction (PPI) networks were constructed. The expression of hub genes at both the mRNA and protein level was determined in Oncomine, The Cancer Genome Atlas (TCGA) and the Human Protein Atlas (HPA). In addition, survival analysis of the patient stratified by HPV status and the expression levels of key genes were performed based on TCGA data. The role of AREG, STAG3, CAV1 and C19orf57 in cancer were analyzed through Gene set enrichment analysis (GSEA). The top ten small molecule drugs were identified and the therapeutic value of zonisamide, NVP-AUY922, PP-2 and fostamatinib was further evaluated in six HPV-negative HNSCC cell lines. Finally, the therapeutic value of NVP-AUY922 was tested in vivo based on three HPV-negative HNSCC models, and statistical analysis was performed.

RESULTS

In total, 47 DEGs were obtained, 11 of which were identified as hub genes. Biological process analysis indicated that the hub genes were associated with the G1/S transition of the mitotic cell cycle. Survival analysis uncovered that the prognostic value of AREG, STAG3, C19orf57 and CAV1 differed between HPV-positive and HPV-negative patients. Gene set enrichment analysis (GSEA) showed the role of AREG, STAG3 and CAV1 in dysregulated pathways of tumor. Ten small molecules were identified as potential drugs specifically for HPV-positive or HPV-negative patients; three-NVP-AUY922, fostamatinib and PP-2-greatly inhibited the proliferation of six HPV-negative HNSCC cell lines in vitro, and NVP-AUY922 inhibited three HPV-negative HNSCC xenografts in vivo.

CONCLUSIONS

In conclusion, AREG, STAG3, C19orf57 and CAV1 are key prognostic factors and potential therapeutic targets in HPV-negative HNSCC. NVP-AUY922, fostamatinib and PP-2 may be effective drugs for HPV-negative HNSCC.

Re-examining HSPC1 inhibitors

HSPC1 is a critical protein in cancer development and progression, including colorectal cancer (CRC). However, clinical trial data reporting the effectiveness of HSPC1 inhibitors on several cancer types has not been as successful as predicted. Furthermore, some N-terminal inhibitors appear to be much more successful than others despite similar underlying mechanisms. This study involved the application of three N-terminal HSPC1 inhibitors, 17-DMAG, NVP-AUY922 and NVP-HSP990 on CRC cells. The effects on client protein levels over time were examined. HSPC1 inhibitors were also applied in combination with chemotherapeutic agents commonly used in CRC treatment (5-fluorouracil, oxaliplatin and irinotecan). As HSPA1A and HSPB1 have anti-apoptotic activity, gene-silencing techniques were employed to investigate the significance of these proteins in HSPC1 inhibitor and chemotherapeutic agent resistance. When comparing the action of the three HSPC1 inhibitors, there are distinct differences in the time course of important client protein degradation events. The differences between HSPC1 inhibitors were also reflected in combination treatment-17-DMAG was more effective compared with NVP-AUY922 in potentiating the cytotoxic effects of 5-fluorouracil, oxaliplatin and irinotecan. This study concludes that there are distinct differences between N-terminal HSPC1 inhibitors, despite their common mode of action. Although treatment with each of the inhibitors results in significant induction of the anti-apoptotic proteins HSPA1A and HSPB1, sensitivity to HSPC1 inhibitors is not improved by gene silencing of HSPA1A or HSPB1. HSPC1 inhibitors potentiate the cytotoxic effects of chemotherapeutic agents in CRC, and this approach is readily available to enter clinical trials. From a translational point of view, there may be great variability in sensitivity to the inhibitors between individual patients.

Methanolic extracts of Solieria robusta inhibits proliferation of oral cancer Ca9-22 cells via apoptosis and oxidative stress

Many red algae-derived natural products are known to have anticancer effects. The biological functions of the red alga Solieria robusta from the Karachi coast (Pakistan) remain unclear. Here, we prepared a methanolic extracts of S. robusta (MESR) to examine its possible anti-oral cancer effects and the corresponding mechanism of action. Cell viability of MESR-incubated oral cancer Ca9-22 cells was dose-responsively decreased (p<0.001). According to a propidium iodide (PI)-based assay the cell cycle distribution was dramatically changed, especially for subG1 accumulation. Annexin V/PI assay of apoptosis using flow cytometry also showed that MESR-incubated Ca9-22 cells were dose-responsively increased (p<0.001). For evaluation of oxidative stress in MESR-incubated Ca9-22 cells, we found that reactive oxygen species (ROS) were overexpressed dose- and time-responsively and mitochondrial depolarization was also increased (p<0.001). Taken together, MESR showed inhibitory effects on oral cancer proliferation coupled with apoptosis and oxidative stress.

Linking signaling pathways to transcriptional programs in breast cancer

Cancer cells acquire genetic and epigenetic alterations that often lead to dysregulation of oncogenic signal transduction pathways, which in turn alters downstream transcriptional programs. Numerous methods attempt to deduce aberrant signaling pathways in tumors from mRNA data alone, but these pathway analysis approaches remain qualitative and imprecise. In this study, we present a statistical method to link upstream signaling to downstream transcriptional response by exploiting reverse phase protein array (RPPA) and mRNA expression data in The Cancer Genome Atlas (TCGA) breast cancer project. Formally, we use an algorithm called affinity regression to learn an interaction matrix between upstream signal transduction proteins and downstream transcription factors (TFs) that explains target gene expression. The trained model can then predict the TF activity, given a tumor sample’s protein expression profile, or infer the signaling protein activity, given a tumor sample’s gene expression profile. Breast cancers are comprised of molecularly distinct subtypes that respond differently to pathway-targeted therapies. We trained our model on the TCGA breast cancer data set and identified subtype-specific and common TF regulators of gene expression. We then used the trained tumor model to predict signaling protein activity in a panel of breast cancer cell lines for which gene expression and drug response data was available. Correlations between inferred protein activities and drug responses in breast cancer cell lines grouped several drugs that are clinically used in combination. Finally, inferred protein activity predicted the clinical outcome within the METABRIC Luminal A cohort, identifying high- and low-risk patient groups within this heterogeneous subtype.